Touch sensitive switches are used in applications such as home appliances (e.g., touch panels on stoves, washers and dryers, blenders, toasters, etc.), and portable devices (e.g., IPOD, telephones). Typical touch sensitive switches utilize resistive film sensing or capacitive sensing. Resistive film sensing utilizes two conductive resistive plates that are separated by a very thin spacer. When a light force is applied to one of the plates contact is made with the other plate and the resistance of the system increases. This in turn increases the voltage and can be used to provide an output. This type of technology can be used for single outputs as well as slider switch type outputs. The drawback to this type of switch is that it relies on the elastic properties of the film (and spacer, adhesives, etc.) to return to a known state when the force is removed.
Capacitive switching detects changes in capacitance due to a switching event, such as the placement of an object or a finger proximate to or in contact with the switch. Capacitive switches differ from the resistive approach above because they require substantially no force to realize switch activation. The actual sensitivity of this type of switch can be tuned via a detection circuit. Capacitive switches beneficially provide immunity to interference and eliminate the need for electro-mechanical switch gear (e.g., pushbuttons or sliding switches). In addition, because there are no moving parts, the failure rate is low. However, known techniques for manufacturing capacitive switches are not well-suited to integrating the switches into three-dimensional support structures (e.g., user interfaces such as control panels). In addition, known capacitive switches cannot be readily integrated into structures having contoured shapes without the use of difficult assembly and alignment processes. Thus, a need has arisen for a capacitive switch that addresses the foregoing. A similar need has arisen for in-molded resistive and shielding elements.